1. Field of the Invention
The present invention relates to the field of odorimetry and, more particularly, to a method of measuring the total concentration of odors of an object, a method of discriminating objects by comparatively analyzing the concentrations of various odors of the objects, and an apparatus for use in carrying out such methods.
2. Description of the Prior Art
Odorimetry plays an important role in the field of quality inspection, for example, when the freshness of perishable foods being shipped is to be evaluated. Other examples include control of fermentation and classification by grade of seaweed, coffee, alcoholic beverages or the like in accordance with odor concentrations. For such quality inspections, it is required not so much to measure individual odors separately but to monitor the total concentration of the odors instantaneously.
Conventionally, the above-mentioned quality inspections have been carried out by odor organoleptic tests, i.e., by the human sense of smell. However, such inspections are possible by only those who have a keen sense of smell and taste as well and also are well trained to perform such inspections. Such training takes a long time. Further, the results of the inspections may differ depending upon the physical conditions of the inspector.
Thus, because of lack of objectivity, it has been recognized that it is difficult to provide an acceptable method of odor measurement which can be used to automatically monitor quality inspection processes.
In the fields of cosmetics or liquors, on the other hand, odors play an important role in determining their quality, thus necessitating quality inspection through analytical measurement of odors. Gas chromatography has frequently been used in the art for the purpose of measuring individual odors separately. The gas chromatography, however, is defective in the following points: (1) The results of measurement vary depending upon particular sampling method used; (2) The measurement has to be carried out by a person skilled to some extent; (3) The apparatus useful for such measurement is relatively costly; and (4) It take a considerable time before the results of measurement are given. Taking the last point (4) into consideration, it can be said that gas chromatography is not suited for an in-situ measurement where it is necessary to provide a real time indication of the concentration of odors.